Engineering topics

Piestrup, M. A.

Publications and source records attributed to Piestrup, M. A..

4 records

NASA NTRS1978

Analysis of bunching of an electron beam at optical wavelengths

This paper presents an analysis of the bunching of an electron beam at optical wavelengths by means of the inverse Cerenkov effect. A laser light beam is used to modulate the velocity of the electrons, and this velocity modulation becomes charge-density modulation after an appropriate drift distance. The effects of energy and angular spread of the electrons are included, as well as the impact of scatterings in the index-matching medium. Bunching can occur with reasonable parameter values and the drift distance is of the order of several centimeters.

Chen, C. K.↗

NASA NTRS1978

Momentum modulation of free electrons by laser light

Measurements have been made of the electron momentum modulation resulting from the inverse Cerenkov interaction with laser light. The experiment utilized 40-MeV particles and a 30-MW Nd:YAG laser. Results are given for the harmonic content of the electron beam as a function of distance along the z-axis, electron bunching for the ideal case, and electron current at the laser frequency normalized to the dc current as a function of distance along the z-axis.

Kimura, W. D.↗

NASA NTRS1976

Laser-electron beam interaction applied to optical amplifiers and oscillators

Momentum modulation of a relativistic electron beam by a Nd:YAG laser is demonstrated. The electrons, at 100 MeV energy, interact with the laser light in helium gas at standard temperature and pressure. At an angle of 6.55 mrad between the two wavevectors, corresponding to the Cerenkov angle, a given electron remains in a field of constant phase as it passes through the light beam. The experimental arrangement is illustrated showing the trajectories of the electron and light. The particle momentum is measured by a mass spectrometer, and the angle between the wavevectors is controlled by a rotatable mirror. Experimental results indicate that momentum modulation of an electron beam may be used for amplification. A possible configuration for an optical klystron is illustrated.

Pantell, R. H.↗

NASA NTRS1975

Momentum modulation of a free electron beam with a laser

A Nd:YAG laser has been used to modulate the energy of a free electron beam. With a single pass of the 2-MW laser light through the 100-MeV electrons we have measured a 37-keV increase in the width of the energy spectrum for the particles. The interaction occurred in helium at standard temperature and pressure over a distance corresponding to 100,000 optical wavelengths, and a phase synchronism condition was maintained by means of the inverse Cerenkov effect. That is, along the direction of motion of the electrons the phase velocity of the electromagnetic wave equaled the electron velocity. Therefore, the electrons remained in an electric field of constant phase, resulting in significant energy exchange.

Piestrup, M. A.↗